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• V1.2 Boards Ordered

  jeremy.geppert • a day ago • 0 comments

  After some more modifications V1.2 has been released to production!

  V1.2 Changes:

  1. The window for the OLED has been narrowed a bit to allow for variation in the OLED displays by batch/manufacturer. One the second batch of OLEDs I ended up having a space on the left that didn't look right.

  2. The addition of a test point pad that traces to GPIO2. This will be for blue wiring to the audio amp stand along circuit board I am going to stick on the back of the board to add sound. I am running out of time and this made the most sense for my skill level. More on those details further down the update.

  3. I moved the polarity jumpers down to the bottom to allow plenty of room for the speaker and amp circuit.

  The Speak and Spell SAO is going to be capable of speaking and spelling!  :)

  After some great input and ideas on the colors, I decided to go with white silkscreen on red mask. I will spray paint the black bar. This will allow me to paint the inside exposed board edge of the OLED window.

  I'll also plan on painting over the OLED pins after soldering in place.

  This is the little mono amp circuit I plan to integrate onto a few of the boards to play with.

  And this is the speaker I am using. Part number and link to digikey will be in the components list on this project. My initial testing of placing the speaker on the backside of the board increased the perceived volume. I'll probably just hot glue it in place so it stays tight to the board and sounds the best.

• V1.1 Boards Arrived

  jeremy.geppert • 3 days ago • 0 comments

  The revised board design arrived that addressed the screen position mistake. This small batch was also an opportunity to try the Black on Red color scheme that PCBX.com allows. The quality of these boards seems lower than those from JLCPCB. I am undecided about which color scheme I go with. The black on red is more costly. I'll be working on adding the speaker/amp to the design and then have to decide what it's going to be for the final batch to bring to Supercon.

• V1.2 Features - Sound

  jeremy.geppert • 5 days ago • 0 comments

  Using CircuitPython running on a RP2040 Zero, an audio amplifier breakout board, and a small speaker I was able to play mp3 files. Certainly good enough for speak and spell quality audio that I'm trying to replicate on this small scale.

  I'll need to figure out how to pump up the volume but this is promising. The board has plenty of room on the back for a speaker and amp circuit yet. The speaker fits perfectly in the handle cutout as is so that is an option too.

• Exploring speech

  jeremy.geppert • 10/05/2024 at 13:12 • 0 comments

  While I'm waiting for the revised boards to arrive I am exploring the V2 feature of adding a small speaker/amp and audio support. The original plan was to have an ESP32 C3 super mini onboard to do cool stuff with the display and speaker. I've now learned that the C3 won't with with the Arduino "Talkie" library I was planning on using. After a consult with brother Andy, I'm looking at a different option:

  MAX98357 I2S 3 Watt Class D Audio Amplifier

  I know nothing about I2S but it appears it is compatible with 2040 based Pis.

  It would be cool to have the board completely independent but it might be more practical to just add the speaker and I2S capabilities and let the host it's plugged into drive it.
  

  More learning and prototyping necessary...

• Great paint tip!

  jeremy.geppert • 10/02/2024 at 22:49 • 2 comments

  @davedarko mentioned a trick of using clear coat before paint when taping something off where you want crisp edges in the comments on the previous log entry. I tried this trick and it worked GREAT! Thanks Dave!

  This will be a great fast and easy way to get the black bar where it needs to be if I end up going with white silkscreen for the final versions. I have 30 of these botched boards to get the technique right on. :/

  I taped it off with just a sliver of red showing as to make sure no white was showing through. Unless you have really good eyes or take a close up photo you won't notice.
  

• V1.1 Ordered!

  jeremy.geppert • 09/29/2024 at 04:38 • 0 comments

  After making the necessary OLED placement revisions and centering the SAO connector I have ordered 10 V1.1 boards from the PCBX which had a great into price on Black Silkscreen on Red Boards. This allows me to test the revision and see how Black on Red really looks. I'll still have time to order more and make another revision if necessary. There are people rooting for me to get to V2 with the speaker/driver circuit working before Supercon. We'll see.

• Paint it, black.

  jeremy.geppert • 09/29/2024 at 01:48 • 3 comments

  @davedarko had a great idea to just tape off the screen bar and hit it with spray paint. That is far much less work than cutting vinyl. I tried that and it worked great. I just need to use fresh tape so I don't get the bleed through on the edge. I think it collects dust on the edges and then allows paint to wick under. Regardless, this will be my solution. I used some semi-gloss black Rustoleum spray paint.

  Thanks for the great simple idea Dave!

  I see a white bar and I want it painted black... [guitar background music]
  

• I like to move it, move it

  jeremy.geppert • 09/28/2024 at 01:40 • 0 comments

  After going down the path of widening the board and killing the scale I realized I could just move the opening for the OLED and associated pins to the left. Duh.

  Here we go now with Rev 1. Printed the template and cut the WHOLE thing out this time. Some margin for variations in OLED boards.

  I'm disappointed I wasn't able to keep the right justified screen like that of the original Speak & Spell, but it's a small concession to save the overall vibe. Shifting left (not that kind) encroached on where I was going to cut holes for the speaker in V2. I'll figure something else out later.

  I'll get another set of eyes on this and then order more boards before the Chinese Holiday.

• Putting the S---! in SAO... Boards arrived!

  jeremy.geppert • 09/27/2024 at 22:23 • 4 comments

  So... today was a roller coaster. The boards arrived and look GREAT!!!!! SO EXCITED!!!!

  Then I installed the OLED... But first, remember how I was so proud of printing the template 1:1 out to make sure the window alignment was good?  Yeah, I nailed that.  BUTTTT... Big smelly BUTT TRUMPET!

  I FAILED TO NOTICE THE OLED BOARD EXTENDING TOO FAR!  I didn't cut out the whole board template, just the window of concern. The rest of the paper covered this HUGE oversight. This is a great example of being to focused on one thing and missing other stuff. Seriously, I KNOW BETTER. This is how we get humbled.
  

  And... I just read the nice article on HackADay.com that Kristina wrote giving my project some love and pointing out the paper template trick. SO.... this a bit embarrassing but I'll own this and maybe this will help others avoid a rookie mistake. Slow down. Phone a friend to look over your shoulder and give you a sanity check.

  Back to good news, I soldered on the components, blacked out the screen frame with a sharpie for now and it works! The signal displayed is for a different sized screen, but I just wanted to see it get power and data. Good enough test for now.

  I have 30 of these sitting here now that represent both success and failure. There is probably some life lesson there but I'm not slowing down to figure it out right now. They are functional. I am leaning towards making a revision and deviating from the scale slightly to hide the OLED board by moving the screen hole and pins left. I think the white keyboard is far more visible than black will be. I am going to likely stick with a white silk screen and Cricut or laser some vinyl sticker for the black bar.

  I do want to include a speaker... but my other SAO (SAO LoRa Walkie Talkie) is almost done and I really want to get that done as well in time for a proof and potential revisions. I have the parts laying here so at a minimum I should have a cobbled together speaker version. And yes, there is a library for the speak & spell voice!!!! THAT IS A MUST.

  The badges need some comms and my brother and I are planning some cool tricks combining his SAOs with the RF capability of my other SAO idea.
  

  Back to struggle bus where the struggle is real but we don't give up!

• Digikey order arrived

  jeremy.geppert • 09/26/2024 at 12:19 • 0 comments

  My digikey order arrived with the momentary switches and connectors I need. The switches are tiny!!!!!!!!!! "Don't sneeze tiny". 

  I will get the BOM and files added to the project once I verify the prototype. The boards are still showing a Friday arrival. I know what my Friday night looks like.

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